1. Field of the Invention
The invention relates to a gas turbine.
2. Description of the Related Art
The fundamental construction of a gas turbine, such as for example an industrial gas turbine, is known in principle to the person skilled in the art addressed here. A gas turbine comprises a compressor, a burner comprising at least one combustion chamber, and a turbine. In the compressor, an air flow is compressed. The compressed air flow can be fed to the or each combustion chamber of the gas turbine. In the or each combustion chamber of the gas turbine, a fuel is combusted in the presence of the compressed air, as a result of which the air is heated. Starting out from the or each combustion chamber of the turbine, the heated air can be fed to the gas turbine, wherein the heated air is expanded in the turbine. The work performance of such a gas turbine is then obtained from the difference of the power output by the turbine and consumed by the compressor. This difference materialises through the energy input in the or each combustion chamber of the burner.
Gas turbines known from practice comprise, furthermore, a diffuser, which seen in flow direction of the expanded air, is arranged downstream of the turbine. For regulating and/or controlling the operation of a gas turbine it is important to determine a so-called thermodynamic mean temperature of the expanded air, which is also described as mixed-out turbine outlet temperature, wherein for this purpose with gas turbines known from practice a plurality of temperature sensors are employed, which are positioned downstream of the turbine and if required upstream of the diffuser in the region of an annular flow duct for the expanded air.
Here there is the problem that over the circumference and the duct height of the flow duct substantial temperature gradients can occur, as a result of which it is required to arrange a multiplicity of temperature sensors over the circumference and the duct height of the flow duct and then determine the thermodynamic mean temperature or the mixed-out turbine outlet temperature of the expanded air with the help of a model of the measurement values detected by the temperature sensors. However, this is not only expensive but dependent on the number of temperature sensors also error-prone.